Deposition of 0.5 to 2 Micron Aerosol in the Human Lung

0.5 至 2 微米气溶胶在人肺中的沉积

• 批准号: 6467616
• 负责人: GORDON KIM PRISK
• 金额: $ 31.5万
• 依托单位: UNIVERSITY OF CALIFORNIA, SAN DIEGO
• 依托单位国家: 美国
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-05-06 至 2004-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6467616
• 关键词: adult human (21+); aerosols; analytical method; biophysics; clinical research; diffusion; environmental contamination; environmental exposure; gravity; human subject; lung injury; mathematical model; model design /development; particle; respiratory function; sedimentation

DESCRIPTION (provided by the applicant): The deposition of small (less than 2.5Mm) particles in the human lung is governed primarily by the mechanisms of sedimentation and diffusion. Recent studies we performed in the microgravity (MG) environment have shown a significant degree of enhanced deposition of small particles, compared to that predicted by existing numerical models of deposition. It seems likely that this results from the previously unaccounted for effects of the non-reversibility of flows in the human lung (effectively providing enhanced diffusion). Such enhanced deposition means that existing models for small particles (less than 2.5 Mm) probably underestimate exposure, and that this increased exposure occurs in the sensitive alveolar regions of the lung. We propose to investigate enhanced alveolar deposition by studying 1) The contribution of diffusion to aerosol dispersion by inclusion of breathhold in aerosol bolus tests: 2) The increase in convective mixing in the lung caused by flow reversals that induces complex mixing of the streamlines in the lung; and 3) The increase in convective mixing in the lung in 1G by performing similar studies using the smallest particles on the ground. To study these effects, we propose to measure regional deposition and dispersion of inhaled boluses of 0.5 and 2 micron particles in MG in the NASA KC-135 Microgravity research Aircraft, and 0.5 micron particles on the ground. By performing these studies in the absence of gravity we will be able to directly study these effects without the confounding influence of sedimentation, a gravitational process. Such direct observations without the influence of sedimentation are not possible in the terrestrial laboratory. There is evidence for many lung diseases beginning in the small airways or alveoli, and increased alveolar deposition through enhanced diffusion may provide a link between long-term MG exposure and lung disease. The results of this study will allow existing models of regional intrapulmonary aerosol deposition to be improved, especially for the smaller particles (those in the range 0.5 to 1 micron). Such information will provide a much-improved basis for the assessment of exposure to small inhaled particles both in long duration spaceflight and on Earth.

描述（由申请人提供）：小额（少于 2.5Mm）颗粒在人肺中主要受以下机制控制： 沉淀和扩散。我们最近在微重力下进行的研究 （MG）环境显示出显着程度的增强沉积 小颗粒，与现有数值模型预测的相比 沉积。看来这很可能是由于之前未计算在内的 对于人肺中流动的不可逆性的影响（有效地 提供增强的扩散）。这种增强的沉积意味着现有的 小颗粒（小于 2.5 毫米）的模型可能低估了暴露量， 并且这种增加的暴露发生在敏感的肺泡区域 肺。我们建议通过研究 1) 来研究增强的肺泡沉积 通过包含屏气来扩散对气溶胶扩散的贡献 在气溶胶推注测试中：2) 肺部对流混合的增加导致 通过流动逆转引起肺部流线的复杂混合； 3) 通过执行 1G 中肺部对流混合的增加 使用地面上最小的颗粒进行类似的研究。要研究这些 影响，我们建议测量吸入的区域沉积和扩散 NASA KC-135 微重力中 MG 中的 0.5 和 2 微米颗粒团 研究飞机和地面上的 0.5 微米颗粒。通过执行这些 在没有重力的情况下进行研究我们将能够直接研究这些 的影响，而没有沉积作用的混杂影响，重力 过程。这种不受沉降影响的直接观察是 这在陆地实验室是不可能的。有证据表明许多肺部 疾病始于小气道或肺泡，并且肺泡增多 通过增强扩散的沉积可能提供长期 MG 之间的联系 暴露和肺部疾病。这项研究的结果将使现有模型 局部肺内气溶胶沉积有待改善，特别是 较小的颗粒（0.5 至 1 微米范围内的颗粒）。此类信息 将为评估小额信贷风险提供一个更加完善的基础 在长时间的太空飞行和地球上吸入颗粒。